Study on Deinking performance of the most popular

2022-09-21
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Research on Deinking performance of water-based UV curable ink

water based ink is mainly composed of hydrophilic acrylic resin, pigment, water and additives. In the conventional alkali deinking process, hydrophilic acrylic resin brings great difficulties to waste paper deinking, mainly because the ink particles peeled off from the fiber in the pulping stage are dispersed very fine, with an average particle size of about 0 0 micron, and has hydrophilicity, which seriously affects the deinking efficiency

it has been studied to improve the deinking performance of water-based ink printed paper and magazine paper by optimizing the deinking process and using appropriate deinking agents, and most of the accidents caused are disastrous improvements in deinking efficiency. However, the conventional alkaline flotation washing deinking technology is not suitable for the treatment of printing waste paper with more than 10% of water-based ink prints

in order to solve this problem, this topic has carried out a preliminary discussion from the aspect of changing the composition of the ink. The prepared water-based light curing ink has been printed and deinked on paper. The experiment is in the stage of equipment manufacturing and civil construction. This ink is a new type of water-based ink. The connecting material of the ink has a hydrophilic group and can be dispersed in water under alkaline conditions; When printed on paper, the ink can be quickly crosslinked and cured under ultraviolet (UV) irradiation to complete the drying process. At present, the printing production can be completed on the flexographic printing machine with UV device

when the newspaper printed with this ink is deinked under conventional alkaline conditions, due to the crosslinking reaction of the binder, the ink particles stripped from the fiber will not be dispersed into very small particles like ordinary water-based ink. If the ink particles are controlled within the range of microns suitable for flotation deinking, the deinking efficiency can be greatly improved

1 experiment

1.1 experimental materials and equipment

paper: quantitative 46.3g/m3, whiteness 57.8%, opacity 94.3%, from Shandong Huatai Paper Group; Water based light curing ink: self made; Oil based ink: produced by Taiyuan ink factory; Water based flexographic ink: produced by Shenzhen Brett Industrial Co., Ltd; Color wheel: made by Shanghai Printing Technology Research Institute; Model 518 reflective densitometer: manufactured by X-Rite company in the United States; UV curing machine: domestic, illumination distance 15 cm, light intensity 80w/cm; Yq-z-48b whiteness tester: domestic; H-272m pulper; L-100 flotation deinking instrument; Fi101 square tablet reader; Residual ink scanner: made in Canada

1.2 experimental methods

1.2.1 simulation printing of different types of inks uses color developing wheels to print different types of black inks on paper, the ink coverage is 25%, oil-based inks and water-based flexographic inks are naturally dried, and water-based light curing inks are immediately dried by UV curing machine after printing. In order to ensure that the ink film thickness of different types of inks is consistent, the print optical density method is used to control the ink film thickness, and the ink amount of each ink is adjusted to make the optical density of the product after drying 1 45. Optical density is measured by reflective densimeter. The paper needed for printing and replacing the spring brush shall be stored for 2 months

1.2.2 shredding of paper

tear the paper printed in 1.2.1 into 25mm*25mm and place it in a sealed bag to balance the moisture. In the high pulper, first add a certain amount of hot water into the pulper, adjust the pulping temperature to 55 ℃, and then add a measured amount of NaOH solution, Na2SiO3, deinking agent, H2O2 and paper containing 80g of absolute dry fiber

1.2.3 flotation

dilute the disintegrated slurry to 1%, pour it into the waste paper flotation deinking instrument, start the circulating slurry pump for 2min, open the inlet valve, and adjust the gas flow 0 12 m3/h, flotation at normal temperature

1.2.4 washing

the slurry after flotation is washed to a concentration of 0.5%, and is washed and concentrated once with 80 mesh copper

1.2.5 sheet making

sheet the shredded slurry or the slurry after flotation washing on the square tablet reader, with a quantitative amount of 60g/m2

1.3 analysis method

the whiteness of paper is measured by whiteness meter. The residual ink scanner is used to analyze according to TAPPI standard t568pm-99, and the distinguishable ink particle size is microns

2 results and discussion

this experiment discussed the deinking performance of Waterborne UV curable inks under the current conventional alkali method. The chemical conditions simulated the conventional deinking. The dosage of chemicals (relative to the absolute dry waste paper) were naoh1%, na2sio32%, deinking agent 0.4%, h2o21% respectively

2.1 according to the experimental data, in the conventional alkali deinking workers, but storage has a certain danger: the site storing recyclable materials has produced hundreds of fires. In the Zai process, the suitable deinking conditions for water-based light curing ink are pulp concentration of 10%, pulp crushing time of 20min, stirring speed of 1500r/min, flotation time of 15min

2.2 under suitable deinking conditions, the deinking efficiency of water-based UV curable ink is close to that of oil-based ink and better than that of water-based flexographic ink. 2.3 water based UV curable ink changes the formula and drying method of traditional water-based ink, and provides a new idea to solve the problem of deinking water-based ink

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